Genetic Diversity Analysis Of Pyropia/Porphyra Yezoensis

Pyropia/Porphyra yezoensis belongs to Phylum Rhodophyta, Classbangiophyceae, Order Bangiales, Family Bangiaceae, Genus Pyropia/Porphyra,distributing in west coast of the Pacifi. It is the model species of the intertidalseaweeds, and is the ideal material for the stress-tolerance molecular physiology.P.yezoensis is widely cultivated in China, Japan and Korea. As it is abundanting withprotein and polysacharide, it has high nutrition value and healthy value. In theaqueculture fo P.yezoensis there is a lot of problems, as the degration of lines,frequent occurrence of disease, less lines et al, result in the lost of product. For thebreeding work, it is important for us to investigate and protect the wild germplasmresources of P.yezoensis. So the genetic diversity of six populations of fourgeographic locations was analyzed by Simple Sequence Repeat (SSR) and InternalTranscript Sequence (ITS). It is aiming at providing therory basis for building thegermplasm repository and help for the breeding work.In the molecular reseach of P.yezoensi, extration of high molecular weightgenomic DNA is one of important steps. As the bead beating homogenizer being used,a protocol for isolation of DNA was developed, it could rapidly and throughput grindsimples. As the second molecular marker, SSR has been used in P.yezoensis, but thedevelopment of SSR is complicated and inefficient. Basee on the survey, SSR hasbeen developed in the genomic level.11polymorphic loci were used to analyze thegenetic diversity of6populations of4geographic locations Dalian, Weihai, Yantaiand Qingdao. Binary data were processed by Popgene32program. UPGMA clusteringanalyzed on computer among these populations. ITS1has been proved that it candistinct P.yezoensis from other species of Pyropia/Porphyra, as there were manypolymorphism site in the sequence of ITS1as the same to5.8S and ITS2. ITS1wasused to identify the samples of the six populations, and the whole sequence of ITSwas used to analyze the genetic diversity of these populations. Results as follow:Four kinds of beads, two different simples (dried and wet), various time for grinding had been used to eptimize the isolation of DNA from blade of P.yezoensis.The optimum condition is with0.2mL metal beads, grinding5s by6800rpm, for wetand dried simples. High quality of DNA could be extracted.56SSR loci had been selected by the proportion of motif in genome, and all theloci had been designed primers. At last11polymorphism loci were obtained. Theywere used to assessment the genetic diversity of6wild populations. The populationsof Qingdao and Dalian had a high genetic diversity, and the populations of Weihai andYantai had low genetic diversity. The genetic distance and coefficient betweenQingdao_ZS and Qingdao_HQ was the0.0091and0.991, while the genetic distanceand coefficient between Yantai and Weihai was0.3487and0.7056. The result ofUPGMA clustering is that three populations of Qingdao were clustered together as thefirst group,and the were clustered together with the Weihai population as secondgroup; while Dalian population and Yantai population were clustered together as onegroup.In wild population,20-28samples in every population had been sucussfullysequenced of ITS. The most samples had been sucussfully sequenced is Qingdao_ZSpopulation, the least is Weihai population. The ITS1sequences of all the sampleswere clustered together with P.yezoensis. The distances of every population was0.0011-0.0129, the distance of Dalian population is0.0129. The P.tenera andP.kinositae had longest distance with P.yezoensis. In the6wild populations, Dalianpopulation had a highest distance with all other5population.The results indicated that the SSR and ITS were useful tools for the analysis ofthe genetic diversity of P.yezoensis. The wild population in china of P.yezoensis had ahigh genetic diversity, could provide germplasm for germplasm repository andbreeding work.